By default, Ubuntu 13.10 cannot play MP3 audio files. We need extra packages installed in order to play MP3 and some other multimedia files. But don't worry, as long as you have a working internet connection, this problem can be solved in matter of seconds.
All we need is to install ubuntu-restricted-extras package. This package will include all the packages needed to play multimedia files including a flash plugin support. To install ubuntu-restricted-extras simply execute this command on Terminal
sudo apt-get install ubuntu-restricted-extras
Once finished, you will be able to play MP3 and YouTube videos using your web browser.
